Dialysis treatment of individuals suffering from renal failure requires that blood be withdrawn and cycled through a dialysis machine that performs the function of the failed kidneys. This process, termed hemodialysis, must be repeated periodically and thus requires repeated puncture wounds using dialysis needles. Moreover, dialysis requires a relatively rapid blood flow rate so the dialysis needle is relatively large. Frequent puncturing of native vessels with large bore needles can cause trauma and eventually a loss of patency.
A common technique to provide vascular access for hemodialysis, therefore, is to connect a prosthetic (AV) graft or shunt between an artery and a vein in, for example, the arm.
Conventional AV grafts are often constructed of polymer material such as expanded polytetrafluoroethylene (ePTFE). ePTFE grafts are generally not self-sealing when punctured and usually require implantation for two or more weeks prior to puncture so that a layer of fibrotic tissue has an opportunity to attach to the outside surface of the graft. The layer of fibrotic tissue prevents blood that leaks through the wall of the graft upon withdrawal of the dialysis needles to form a hematoma between the graft and surrounding tissue. This hematoma could cause adverse events such as lack of incorporation of the graft and increased chance for infection. Prior to the two week incorporation time, a central venous catheter (CVC) is often utilized to access the blood required for cycling through the dialysis machine. The CVC, however, exposes the patient to risks such as infection and the destruction of potential access sites distal to the CVC.
Self-sealing vascular access grafts have been designed that ostensibly do not require an extended period of time for healing and tissue growth before being punctured. Such grafts can be accessed sooner after surgery as shown, for example, in U.S. Pat. Nos. 4,619,641 and 5,116,360. Complete success has not been obtained from such grafts, however, since some still exhibit excessive leakage when punctured less than two weeks after being implanted. Additionally, some self-sealing grafts, due to their multi-layered construction, may be unable to distend sufficiently upon a change in arterial blood pressure. Furthermore, known self-sealing grafts may have a bulky construction that interferes with the sensing of blood pressure pulsation. Excessive structure in some self-sealing grafts acts to attenuate the blood pressure pulse and makes the search for the graft much harder for medical personnel attempting to establish a dialysis circuit.
Thus, there is a need for an early access, self-sealing, compliant and non-bulky AV graft for use with hemodialysis. The present invention meets these and other needs as described herein.